[BUG] A local `directory` type `extraKnownMarketplaces` is not automatically added

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

We have the following setup in .claude/settings.json in a repository:

"extraKnownMarketplaces": {
    "internal-marketplace": {
      "source": {
        "source": "directory",
        "path": "./.claude"
      }
    }
  }

When I start up claude in this repository, I expect internal-marketplace to be automatically added to /plugin > Marketplaces.
However it's not showing up there.

Running this from the terminal works, the marketplace is set up correctly in .claude/.claude-plugin/marketplace.json:

claude plugin marketplace add ./.claude

What Should Happen?

The local directory marketplace should be automatically added to /plugin > Marketplaces.

Error Messages/Logs

Steps to Reproduce

1. Add a single directory marketplace to extraKnownMarketplaces (no github or other markeplaces)
2. Run claude.
3. Run /plugin and go to Marketplaces tab.
4. The local marketplace is not there.

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.6

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Warp

Additional Information

During troubleshooting I can see that internal-marketplace shows up for a brief moment in my ~/.claude/plugins/known_marketplaces.json and then instantly disappears, when I start up claude. I can also "fix" it if I add any github marketplace.

My guess is there is some parallel process on startup that updates known_marketplaces.json and for some reason erases the directory marketplace. Adding github marketplace adds enough fetching delay so that known_marketplaces.json is updated after that other parallel process.